From f17d5198c547b208379e523bf400e55cef88ff56 Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.org>
Date: Tue, 30 Jun 2015 14:12:42 +0100
Subject: [PATCH] serial: 8250: Don't crash when nr_uarts is 0

---
 drivers/tty/serial/8250/8250_core.c | 2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -509,6 +509,8 @@ static void __init serial8250_isa_init_p
 
 	if (nr_uarts > UART_NR)
 		nr_uarts = UART_NR;
+	if (!nr_uarts)
+		return;
 
 	for (i = 0; i < nr_uarts; i++) {
 		struct uart_8250_port *up = &serial8250_ports[i];
